Do you have the counter weight? This is a heavy weight with 4 wheels on it which moves up and down the inside of the track and must be used. The flat trailing cable loops around the counter weight.
The static chain must also be anchored at the top and bottom of the rail and the safety gear has to be released for the lift to work. This can be done by lifting the chain up (on the section of rail just above the stairlift motor) whilst supporting the weight of the stairlift.
Dolphin Stairlifts, November 2011